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  <h1 data-lake-id="lVRaC" id="lVRaC"><span data-lake-id="u1c10a3ba" id="u1c10a3ba">面试者背景</span></h1>
  <p data-lake-id="ua6a387a6" id="ua6a387a6"><br></p>
  <blockquote data-lake-id="u9afe6761" id="u9afe6761" class="lake-alert lake-alert-warning">
   <p data-lake-id="ue066a78f" id="ue066a78f"><span data-lake-id="ubbbb508f" id="ubbbb508f" class="lake-fontsize-12">3年经验，2家公司（新能源，to B业务），智慧园区-智慧物业-能耗管理</span></p>
   <p data-lake-id="u4defe57b" id="u4defe57b" style="text-align: left"><span data-lake-id="u34908bbd" id="u34908bbd" class="lake-fontsize-12">能耗管理业务介绍一下，智能控制、能耗统计、性能优化、数据准确度提升、稳定性，</span></p>
   <p data-lake-id="u5213d75f" id="u5213d75f" style="text-align: left"><span data-lake-id="u5d00d368" id="u5d00d368" class="lake-fontsize-12">性能优化、数据准确度、稳定性，分别做了哪些事情？换成</span><span data-lake-id="u7911a514" id="u7911a514" class="lake-fontsize-12">adb</span><span data-lake-id="u15870f1c" id="u15870f1c" class="lake-fontsize-12">、业务宽表拆解，</span></p>
   <p data-lake-id="ucf0cf2e4" id="ucf0cf2e4" style="text-align: left"><span data-lake-id="u8808914e" id="u8808914e" class="lake-fontsize-12">数据库切换如何保证的稳定？代码中多数据源的管理是怎么做的？</span></p>
   <p data-lake-id="u11b295da" id="u11b295da" style="text-align: left"><span data-lake-id="ubba7064f" id="ubba7064f" class="lake-fontsize-12">为啥</span><span data-lake-id="ubdef020b" id="ubdef020b" class="lake-fontsize-12">adb</span><span data-lake-id="u069a21ba" id="u069a21ba" class="lake-fontsize-12">查询快知道么？</span></p>
   <p data-lake-id="u110fd9a6" id="u110fd9a6" style="text-align: left"><span data-lake-id="u1ccea6f5" id="u1ccea6f5" class="lake-fontsize-12">项目中有难度的地方有吗？</span></p>
   <p data-lake-id="u2586b01a" id="u2586b01a" style="text-align: left"><span data-lake-id="u67675959" id="u67675959" class="lake-fontsize-12">Netty</span><span data-lake-id="u0bc2298a" id="u0bc2298a" class="lake-fontsize-12">相比原生的</span><span data-lake-id="u62102aa7" id="u62102aa7" class="lake-fontsize-12">IO</span><span data-lake-id="uc074ae98" id="uc074ae98" class="lake-fontsize-12">模型有啥优势？封装</span><span data-lake-id="u8933798a" id="u8933798a" class="lake-fontsize-12">NIO</span><span data-lake-id="u260ba934" id="u260ba934" class="lake-fontsize-12">、粘包</span><span data-lake-id="ucf2d9a17" id="ucf2d9a17" class="lake-fontsize-12">/</span><span data-lake-id="u7af8830d" id="u7af8830d" class="lake-fontsize-12">拆包、</span><span data-lake-id="u5d460e7e" id="u5d460e7e" class="lake-fontsize-12">IO</span><span data-lake-id="ue6e9c3ee" id="ue6e9c3ee" class="lake-fontsize-12">多路复用、</span><span data-lake-id="u997d9e77" id="u997d9e77" class="lake-fontsize-12">reactor</span><span data-lake-id="u930062c1" id="u930062c1" class="lake-fontsize-12">模型</span></p>
   <p data-lake-id="u2da458f2" id="u2da458f2" style="text-align: left"><span data-lake-id="ucdf69691" id="ucdf69691" class="lake-fontsize-12">为啥</span><span data-lake-id="u175c6013" id="u175c6013" class="lake-fontsize-12">Netty</span><span data-lake-id="u5b90e9c9" id="u5b90e9c9" class="lake-fontsize-12">不基于</span><span data-lake-id="ud7508129" id="ud7508129" class="lake-fontsize-12">AIO</span><span data-lake-id="ucbaaba9b" id="ucbaaba9b" class="lake-fontsize-12">做呢。</span><span data-lake-id="uc151b1bb" id="uc151b1bb" class="lake-fontsize-12">NIO</span><span data-lake-id="u80e353e9" id="u80e353e9" class="lake-fontsize-12">用的是堆内内存还是堆外内存？</span><span data-lake-id="u09c9cca6" id="u09c9cca6" class="lake-fontsize-12">directByteBuffer</span><span data-lake-id="u8d6b92f1" id="u8d6b92f1" class="lake-fontsize-12">为啥用堆外内存？零拷贝，堆外内存溢出如何排查，</span><span data-lake-id="u9436959d" id="u9436959d" class="lake-fontsize-12">dump</span><span data-lake-id="u81761fa2" id="u81761fa2" class="lake-fontsize-12">对堆外内存有用吗？</span><span data-lake-id="ud235a430" id="ud235a430" class="lake-fontsize-12">netty</span><span data-lake-id="ua69f68b3" id="ua69f68b3" class="lake-fontsize-12">适合用在什么场景中？</span><span data-lake-id="ue100570f" id="ue100570f" class="lake-fontsize-12">im</span><span data-lake-id="ue4809b92" id="ue4809b92" class="lake-fontsize-12">、通信、</span></p>
   <p data-lake-id="uf2364663" id="uf2364663" style="text-align: left"><span data-lake-id="u54a1d288" id="u54a1d288" class="lake-fontsize-12">Innodb</span><span data-lake-id="u674c3e1d" id="u674c3e1d" class="lake-fontsize-12">的索引介绍下？</span><span data-lake-id="u464aeeb7" id="u464aeeb7" class="lake-fontsize-12">B+</span><span data-lake-id="uf5625011" id="uf5625011" class="lake-fontsize-12">树。</span><span data-lake-id="u9cd061be" id="u9cd061be" class="lake-fontsize-12">Innodb</span><span data-lake-id="u72a24c1a" id="u72a24c1a" class="lake-fontsize-12">中的</span><span data-lake-id="u04b898ed" id="u04b898ed" class="lake-fontsize-12">B+</span><span data-lake-id="uc0c29a1c" id="uc0c29a1c" class="lake-fontsize-12">树长什么样？只有叶子节点之间有双向指针吗？叶子节点的没条记录之间是如何关联的？</span></p>
   <p data-lake-id="uf1ba4071" id="uf1ba4071" style="text-align: left"><span data-lake-id="u5307dcc0" id="u5307dcc0" class="lake-fontsize-12">Innodb</span><span data-lake-id="u326670b1" id="u326670b1" class="lake-fontsize-12">的索引结构和</span><span data-lake-id="u1cf829ab" id="u1cf829ab" class="lake-fontsize-12">myisam</span><span data-lake-id="ue1b8ef7e" id="ue1b8ef7e" class="lake-fontsize-12">有区别吗？</span><span data-lake-id="u51fa85e4" id="u51fa85e4" class="lake-fontsize-12">myisam</span><span data-lake-id="u2a9a0115" id="u2a9a0115" class="lake-fontsize-12">有聚簇索引吗？</span></p>
   <p data-lake-id="u00ca1793" id="u00ca1793" style="text-align: left"><span data-lake-id="u2ea01229" id="u2ea01229" class="lake-fontsize-12">创建索引的时候需要考虑哪些问题？使用频率、查询条件、前缀长度、</span></p>
   <p data-lake-id="u3f236db1" id="u3f236db1" style="text-align: left"><span data-lake-id="u08f3b7da" id="u08f3b7da" class="lake-fontsize-12">什么时候会考虑用联合索引？如果只有一个条件查就没有建联合索引的必要了么？</span></p>
   <p data-lake-id="ud3a4e4b2" id="ud3a4e4b2" style="text-align: left"><span data-lake-id="uc1c9d378" id="uc1c9d378" class="lake-fontsize-12">索引是越多越好么？</span><span data-lake-id="u7df87fb9" id="u7df87fb9" class="lake-fontsize-12">a,b</span><span data-lake-id="u6fcc8c81" id="u6fcc8c81" class="lake-fontsize-12">联合索引，在写</span><span data-lake-id="u64254c34" id="u64254c34" class="lake-fontsize-12">SQL</span><span data-lake-id="ua7ec7b4a" id="ua7ec7b4a" class="lake-fontsize-12">的时候</span><span data-lake-id="ue66d133e" id="ue66d133e" class="lake-fontsize-12">where a = xx and b=xx </span><span data-lake-id="uaff35675" id="uaff35675" class="lake-fontsize-12">的顺序有关系吗？</span></p>
   <p data-lake-id="uc3cf82c7" id="uc3cf82c7" style="text-align: left"><span data-lake-id="ub9f214a3" id="ub9f214a3" class="lake-fontsize-12">Mysql</span><span data-lake-id="u1fdf7cb9" id="u1fdf7cb9" class="lake-fontsize-12">优化器都会做哪些方面的优化？索引选择。</span></p>
   <p data-lake-id="ue4f9b60f" id="ue4f9b60f" style="text-align: left"><span data-lake-id="u6c8884bf" id="u6c8884bf" class="lake-fontsize-12">如果优化器选错了索引怎么办？</span><span data-lake-id="u263b5555" id="u263b5555" class="lake-fontsize-12">force index</span></p>
   <p data-lake-id="ub67a34c3" id="ub67a34c3" style="text-align: left"><span data-lake-id="ub00cbee1" id="ub00cbee1" class="lake-fontsize-12">有哪些情况会导致慢</span><span data-lake-id="u076c23ae" id="u076c23ae" class="lake-fontsize-12">SQL</span><span data-lake-id="ufbbd1a4f" id="ufbbd1a4f" class="lake-fontsize-12">？没走索引、索引失效、数据量大、多表</span><span data-lake-id="u3ea0bb55" id="u3ea0bb55" class="lake-fontsize-12">join</span><span data-lake-id="u237cb91e" id="u237cb91e" class="lake-fontsize-12">、</span></p>
   <p data-lake-id="u4c49bf16" id="u4c49bf16" style="text-align: left"><span data-lake-id="uef812142" id="uef812142" class="lake-fontsize-12">有没有可能走了索引还是很慢？如何确认一个</span><span data-lake-id="ucaf6314f" id="ucaf6314f" class="lake-fontsize-12">SQL</span><span data-lake-id="u87a3a64e" id="u87a3a64e" class="lake-fontsize-12">有没有走索引？</span><span data-lake-id="u59928d9c" id="u59928d9c" class="lake-fontsize-12">type</span><span data-lake-id="ubac375b7" id="ubac375b7" class="lake-fontsize-12">、</span><span data-lake-id="ua51a8c06" id="ua51a8c06" class="lake-fontsize-12">extra</span><span data-lake-id="ub2209d2f" id="ub2209d2f" class="lake-fontsize-12">，</span></p>
   <p data-lake-id="ub893211d" id="ub893211d" style="text-align: left"><span data-lake-id="u01446669" id="u01446669" class="lake-fontsize-12">using index</span><span data-lake-id="ud59fc56e" id="ud59fc56e" class="lake-fontsize-12">是什么意思？</span><span data-lake-id="u678995ed" id="u678995ed" class="lake-fontsize-12">using where</span><span data-lake-id="u5ed64599" id="u5ed64599" class="lake-fontsize-12">一定没走索引吗？</span></p>
   <p data-lake-id="ua82d6059" id="ua82d6059" style="text-align: left"><span data-lake-id="u4c7ee545" id="u4c7ee545" class="lake-fontsize-12">Mysql</span><span data-lake-id="u92d82943" id="u92d82943" class="lake-fontsize-12">的主从原理介绍一下。主从延迟如何排查？</span></p>
   <p data-lake-id="ua64e8840" id="ua64e8840" style="text-align: left"><span data-lake-id="ue6de3d64" id="ue6de3d64" class="lake-fontsize-12">Mysql</span><span data-lake-id="u67f89578" id="u67f89578" class="lake-fontsize-12">中用</span><span data-lake-id="ub3b4a1cb" id="ub3b4a1cb" class="lake-fontsize-12">like</span><span data-lake-id="ua3b263cc" id="ua3b263cc" class="lake-fontsize-12">能走索引吗？‘</span><span data-lake-id="u657c3b3a" id="u657c3b3a" class="lake-fontsize-12">abc%</span><span data-lake-id="ua741ae25" id="ua741ae25" class="lake-fontsize-12">’可以，‘</span><span data-lake-id="u6ec555d5" id="u6ec555d5" class="lake-fontsize-12">%abc</span><span data-lake-id="ubd176201" id="ubd176201" class="lake-fontsize-12">’这种有办法优化吗？</span></p>
   <p data-lake-id="ud16396c7" id="ud16396c7" style="text-align: left"><span data-lake-id="uf0d8cca7" id="uf0d8cca7" class="lake-fontsize-12">Mysql</span><span data-lake-id="uffea3a79" id="uffea3a79" class="lake-fontsize-12">了解过</span><span data-lake-id="u22f1c571" id="u22f1c571" class="lake-fontsize-12">8.0</span><span data-lake-id="ufb7c6f62" id="ufb7c6f62" class="lake-fontsize-12">吗？</span><span data-lake-id="u87939faa" id="u87939faa" class="lake-fontsize-12">redis</span><span data-lake-id="u1924500a" id="u1924500a" class="lake-fontsize-12">有一批</span><span data-lake-id="u6f825096" id="u6f825096" class="lake-fontsize-12">key</span><span data-lake-id="uf9e81b12" id="uf9e81b12" class="lake-fontsize-12">瞬时过期了，会导致什么问题？怎么解决呢？</span></p>
   <p data-lake-id="u235e6e2a" id="u235e6e2a" style="text-align: left"><span data-lake-id="u1dee5226" id="u1dee5226" class="lake-fontsize-12">redis</span><span data-lake-id="ueeac5452" id="ueeac5452" class="lake-fontsize-12">有一批</span><span data-lake-id="ua01340a2" id="ua01340a2" class="lake-fontsize-12">key</span><span data-lake-id="u97c65563" id="u97c65563" class="lake-fontsize-12">瞬时过期了，除了影响数据库，还有其他影响吗？读写会变慢吗？单线程。</span></p>
   <p data-lake-id="ud3361f3d" id="ud3361f3d" style="text-align: left"><span data-lake-id="uac4923e0" id="uac4923e0" class="lake-fontsize-12">Key</span><span data-lake-id="u1922f2c2" id="u1922f2c2" class="lake-fontsize-12">过期会立即删除吗？</span><span data-lake-id="uf082d692" id="uf082d692" class="lake-fontsize-12">redis</span><span data-lake-id="u95da546d" id="u95da546d" class="lake-fontsize-12">的</span><span data-lake-id="u58968b51" id="u58968b51" class="lake-fontsize-12">big key</span><span data-lake-id="u61b20831" id="u61b20831" class="lake-fontsize-12">问题？很大是多大？会有什么问题？如何解决呢？怎么拆？按照日期</span></p>
   <p data-lake-id="u4ba525cc" id="u4ba525cc" style="text-align: left"><span data-lake-id="u80048149" id="u80048149" class="lake-fontsize-12">分库分表介绍下？单表数据量大导致查询慢，除了考虑分表之外，还有哪些方案？归档（冷热分离）、缓存、</span></p>
   <p data-lake-id="u835a2e94" id="u835a2e94" style="text-align: left"><span data-lake-id="u634ed393" id="u634ed393" class="lake-fontsize-12">数据量的话，你觉得做分库分表一定是一个好的方案吗？</span></p>
  </blockquote>
  <h1 data-lake-id="FChSX" id="FChSX"><span data-lake-id="ubd560f90" id="ubd560f90">题目解析</span></h1>
  <p data-lake-id="u26e467c5" id="u26e467c5"><br></p>
  <p data-lake-id="udb1e4b99" id="udb1e4b99"><br></p>
  <blockquote data-lake-id="u6899ae75" id="u6899ae75" class="lake-alert lake-alert-color4">
   <p data-lake-id="u381ec38e" id="u381ec38e" style="text-align: left"><span data-lake-id="u2497da37" id="u2497da37" class="lake-fontsize-12">Netty</span><span data-lake-id="ud708a77a" id="ud708a77a" class="lake-fontsize-12">相比原生的</span><span data-lake-id="u3a1ff740" id="u3a1ff740" class="lake-fontsize-12">IO</span><span data-lake-id="udf550297" id="udf550297" class="lake-fontsize-12">模型有啥优势？封装</span><span data-lake-id="u036297d8" id="u036297d8" class="lake-fontsize-12">NIO</span><span data-lake-id="u1deaeb6e" id="u1deaeb6e" class="lake-fontsize-12">、粘包</span><span data-lake-id="u58958460" id="u58958460" class="lake-fontsize-12">/</span><span data-lake-id="u3b31b62d" id="u3b31b62d" class="lake-fontsize-12">拆包、</span><span data-lake-id="u5e099ea4" id="u5e099ea4" class="lake-fontsize-12">IO</span><span data-lake-id="uc68912aa" id="uc68912aa" class="lake-fontsize-12">多路复用、</span><span data-lake-id="u1a2f4b00" id="u1a2f4b00" class="lake-fontsize-12">reactor</span><span data-lake-id="u78515b04" id="u78515b04" class="lake-fontsize-12">模型</span></p>
   <p data-lake-id="u2d9d1ab9" id="u2d9d1ab9" style="text-align: left"><span data-lake-id="u5d553ce7" id="u5d553ce7" class="lake-fontsize-12">为啥Netty不基于AIO做呢。NIO用的是堆内内存还是堆外内存？directByteBuffer为啥用堆外内存？零拷贝，堆外内存溢出如何排查，dump对堆外内存有用吗？netty适合用在什么场景中？im、通信、</span></p>
  </blockquote>
  <p data-lake-id="u540cf76b" id="u540cf76b"><br></p>
  <p data-lake-id="u8ad5b244" id="u8ad5b244"><a href="https://www.yuque.com/hollis666/vhr2ge/itxx9r" data-lake-id="ua34aba70" id="ua34aba70"><span data-lake-id="u27e1e095" id="u27e1e095">https://www.yuque.com/hollis666/vhr2ge/itxx9r</span></a></p>
  <p data-lake-id="u4e29e5ef" id="u4e29e5ef"><span data-lake-id="ud2d859d4" id="ud2d859d4">​</span><br></p>
  <p data-lake-id="u5b791033" id="u5b791033"><a href="https://www.yuque.com/hollis666/vhr2ge/roit5c9y04z6fqae" data-lake-id="u3f54752a" id="u3f54752a"><span data-lake-id="uefd551f7" id="uefd551f7">https://www.yuque.com/hollis666/vhr2ge/roit5c9y04z6fqae</span></a></p>
  <p data-lake-id="uec385790" id="uec385790"><br></p>
  <blockquote data-lake-id="u7f4aad47" id="u7f4aad47" class="lake-alert lake-alert-color4">
   <p data-lake-id="u0a6e45b8" id="u0a6e45b8" style="text-align: left"><span data-lake-id="uef7fdb6f" id="uef7fdb6f" class="lake-fontsize-12">Innodb的索引介绍下？B+树。Innodb中的B+树长什么样？只有叶子节点之间有双向指针吗？叶子节点的没条记录之间是如何关联的？</span></p>
   <p data-lake-id="u9005c624" id="u9005c624" style="text-align: left"><span data-lake-id="u306bf0cf" id="u306bf0cf" class="lake-fontsize-12">Innodb的索引结构和myisam有区别吗？myisam有聚簇索引吗？</span></p>
  </blockquote>
  <p data-lake-id="u8f7e6905" id="u8f7e6905"><br></p>
  <p data-lake-id="ufcd48e3b" id="ufcd48e3b"><a href="https://www.yuque.com/hollis666/vhr2ge/uh3cy1" data-lake-id="u637afbd0" id="u637afbd0"><span data-lake-id="uf618ceaf" id="uf618ceaf">https://www.yuque.com/hollis666/vhr2ge/uh3cy1</span></a></p>
  <p data-lake-id="u79f71eb5" id="u79f71eb5"><br></p>
  <p data-lake-id="ua8289e38" id="ua8289e38"><a href="https://www.yuque.com/hollis666/vhr2ge/mcl4sn8mcutieesz" data-lake-id="u05846999" id="u05846999"><span data-lake-id="u12226f5e" id="u12226f5e">https://www.yuque.com/hollis666/vhr2ge/mcl4sn8mcutieesz</span></a></p>
  <p data-lake-id="u70793d9a" id="u70793d9a"><br></p>
  <blockquote data-lake-id="ueb56b28d" id="ueb56b28d" class="lake-alert lake-alert-color4">
   <p data-lake-id="ue3e98927" id="ue3e98927" style="text-align: left"><span data-lake-id="u10f0689e" id="u10f0689e" class="lake-fontsize-12">创建索引的时候需要考虑哪些问题？使用频率、查询条件、前缀长度、</span></p>
   <p data-lake-id="u3ec74155" id="u3ec74155" style="text-align: left"><span data-lake-id="uf87f848a" id="uf87f848a" class="lake-fontsize-12">什么时候会考虑用联合索引？如果只有一个条件查就没有建联合索引的必要了么？</span></p>
   <p data-lake-id="uf37add9b" id="uf37add9b" style="text-align: left"><span data-lake-id="u4beeeeac" id="u4beeeeac" class="lake-fontsize-12">索引是越多越好么？</span></p>
  </blockquote>
  <p data-lake-id="uca0c21db" id="uca0c21db"><br></p>
  <p data-lake-id="u70e2de9c" id="u70e2de9c"><a href="https://www.yuque.com/hollis666/vhr2ge/ygxb9f" data-lake-id="ufcc61f86" id="ufcc61f86"><span data-lake-id="udf6e1ce1" id="udf6e1ce1">https://www.yuque.com/hollis666/vhr2ge/ygxb9f</span></a></p>
  <p data-lake-id="uf86dbfde" id="uf86dbfde"><br></p>
  <blockquote data-lake-id="ua7c3642e" id="ua7c3642e" class="lake-alert lake-alert-color4">
   <p data-lake-id="u5e329cba" id="u5e329cba" style="text-align: left"><span data-lake-id="u4c5a5d47" id="u4c5a5d47" class="lake-fontsize-12">a,b联合索引，在写SQL的时候where a = xx and b=xx 的顺序有关系吗？</span></p>
   <p data-lake-id="ud83ef891" id="ud83ef891" style="text-align: left"><span data-lake-id="u49664623" id="u49664623" class="lake-fontsize-12">Mysql</span><span data-lake-id="u89fac456" id="u89fac456" class="lake-fontsize-12">优化器都会做哪些方面的优化？索引选择。</span></p>
   <p data-lake-id="u5e370249" id="u5e370249" style="text-align: left"><span data-lake-id="u2a9e0570" id="u2a9e0570" class="lake-fontsize-12">如果优化器选错了索引怎么办？force index</span></p>
  </blockquote>
  <p data-lake-id="u66a77a41" id="u66a77a41"><br></p>
  <p data-lake-id="u7c37e5d0" id="u7c37e5d0"><a href="https://www.yuque.com/hollis666/vhr2ge/nwm3ry85o8l0gega" data-lake-id="u66f6ba2c" id="u66f6ba2c"><span data-lake-id="u92951780" id="u92951780">https://www.yuque.com/hollis666/vhr2ge/nwm3ry85o8l0gega</span></a></p>
  <p data-lake-id="uc9d4589d" id="uc9d4589d"><span data-lake-id="u280aabe8" id="u280aabe8">​</span><br></p>
  <p data-lake-id="u7c065ff2" id="u7c065ff2"><a href="https://www.yuque.com/hollis666/vhr2ge/st7he2np7e9trg9k" data-lake-id="u9771515e" id="u9771515e"><span data-lake-id="ua2519964" id="ua2519964">https://www.yuque.com/hollis666/vhr2ge/st7he2np7e9trg9k</span></a></p>
  <p data-lake-id="u44773c57" id="u44773c57"><br></p>
  <p data-lake-id="u76d6cded" id="u76d6cded"><br></p>
  <blockquote data-lake-id="ucc727cb1" id="ucc727cb1" class="lake-alert lake-alert-color4">
   <p data-lake-id="u6d25ac9b" id="u6d25ac9b" style="text-align: left"><span data-lake-id="u63f70221" id="u63f70221" class="lake-fontsize-12">有哪些情况会导致慢SQL？没走索引、索引失效、数据量大、多表join、</span></p>
   <p data-lake-id="u982f41fe" id="u982f41fe" style="text-align: left"><span data-lake-id="u227e7c31" id="u227e7c31" class="lake-fontsize-12">有没有可能走了索引还是很慢？</span></p>
  </blockquote>
  <p data-lake-id="ue1c48aa2" id="ue1c48aa2"><br></p>
  <p data-lake-id="ua642a2b3" id="ua642a2b3"><a href="https://www.yuque.com/hollis666/vhr2ge/zhfa5g" data-lake-id="u8404ae83" id="u8404ae83"><span data-lake-id="u22046e9a" id="u22046e9a">https://www.yuque.com/hollis666/vhr2ge/zhfa5g</span></a></p>
  <p data-lake-id="u60ea4d87" id="u60ea4d87"><span data-lake-id="u1ae725bf" id="u1ae725bf">​</span><br></p>
  <p data-lake-id="u581efa47" id="u581efa47"><a href="https://www.yuque.com/hollis666/vhr2ge/st7he2np7e9trg9k" data-lake-id="ub916b898" id="ub916b898"><span data-lake-id="uaf7b63f2" id="uaf7b63f2">https://www.yuque.com/hollis666/vhr2ge/st7he2np7e9trg9k</span></a></p>
  <p data-lake-id="u9df7f9e0" id="u9df7f9e0"><br></p>
  <blockquote data-lake-id="u502f36e5" id="u502f36e5" class="lake-alert lake-alert-color4">
   <p data-lake-id="ud7e7de6d" id="ud7e7de6d" style="text-align: left"><span data-lake-id="uc2cf2308" id="uc2cf2308" class="lake-fontsize-12">如何确认一个SQL有没有走索引？type、extra，</span></p>
   <p data-lake-id="u302ed4eb" id="u302ed4eb" style="text-align: left"><span data-lake-id="uba63f20d" id="uba63f20d" class="lake-fontsize-12">using index是什么意思？using where一定没走索引吗？</span></p>
  </blockquote>
  <p data-lake-id="u7eb4f590" id="u7eb4f590"><br></p>
  <p data-lake-id="u3865d699" id="u3865d699"><br></p>
  <p data-lake-id="uba1c282f" id="uba1c282f"><a href="https://www.yuque.com/hollis666/vhr2ge/fho0bamf4qpcril5" data-lake-id="u63725041" id="u63725041"><span data-lake-id="u77e86c85" id="u77e86c85">https://www.yuque.com/hollis666/vhr2ge/fho0bamf4qpcril5</span></a></p>
  <p data-lake-id="u195c3d91" id="u195c3d91"><br></p>
  <blockquote data-lake-id="ueb7ad9bd" id="ueb7ad9bd" class="lake-alert lake-alert-color4">
   <p data-lake-id="u9a3fdb6b" id="u9a3fdb6b" style="text-align: left"><span data-lake-id="u50cbd7c4" id="u50cbd7c4" class="lake-fontsize-12">Mysql的主从原理介绍一下。主从延迟如何排查？</span></p>
  </blockquote>
  <p data-lake-id="ucbb6f007" id="ucbb6f007"><br></p>
  <p data-lake-id="u368acd06" id="u368acd06"><a href="https://www.yuque.com/hollis666/vhr2ge/hoi4ql" data-lake-id="u6c64c76b" id="u6c64c76b"><span data-lake-id="u2bd3749f" id="u2bd3749f">https://www.yuque.com/hollis666/vhr2ge/hoi4ql</span></a></p>
  <p data-lake-id="u487b2bd8" id="u487b2bd8"><br></p>
  <blockquote data-lake-id="ua6c127e7" id="ua6c127e7" class="lake-alert lake-alert-color4">
   <p data-lake-id="u733b1978" id="u733b1978" style="text-align: left"><span data-lake-id="u2e991dbc" id="u2e991dbc" class="lake-fontsize-12">Mysql中用like能走索引吗？‘abc%’可以，‘%abc’这种有办法优化吗？</span></p>
  </blockquote>
  <p data-lake-id="u8a7742e3" id="u8a7742e3"><br></p>
  <p data-lake-id="uaa6f00cd" id="uaa6f00cd"><a href="https://www.yuque.com/hollis666/vhr2ge/zrt2y30mhdgiremc" data-lake-id="u003f5181" id="u003f5181"><span data-lake-id="u5aeb50af" id="u5aeb50af">https://www.yuque.com/hollis666/vhr2ge/zrt2y30mhdgiremc</span></a></p>
  <p data-lake-id="u51d4c3b5" id="u51d4c3b5"><br></p>
  <blockquote data-lake-id="u3b8c7c96" id="u3b8c7c96" class="lake-alert lake-alert-color4">
   <p data-lake-id="ua8154ba9" id="ua8154ba9" style="text-align: left"><span data-lake-id="uf0018b70" id="uf0018b70" class="lake-fontsize-12">Mysql了解过8.0吗？</span></p>
  </blockquote>
  <p data-lake-id="u5f99b99e" id="u5f99b99e"><br></p>
  <p data-lake-id="ue0646269" id="ue0646269"><a href="https://www.yuque.com/hollis666/vhr2ge/uxdmro" data-lake-id="u0e70a79c" id="u0e70a79c"><span data-lake-id="uf1f7343e" id="uf1f7343e">https://www.yuque.com/hollis666/vhr2ge/uxdmro</span></a></p>
  <p data-lake-id="u65c0b07c" id="u65c0b07c"><br></p>
  <blockquote data-lake-id="u221ba022" id="u221ba022" class="lake-alert lake-alert-color4">
   <p data-lake-id="u068a60e7" id="u068a60e7" style="text-align: left"><span data-lake-id="u81a13da0" id="u81a13da0" class="lake-fontsize-12">redis有一批key瞬时过期了，会导致什么问题？怎么解决呢？</span></p>
   <p data-lake-id="u21896b90" id="u21896b90" style="text-align: left"><span data-lake-id="uf6dea4d5" id="uf6dea4d5" class="lake-fontsize-12">redis有一批key瞬时过期了，除了影响数据库，还有其他影响吗？读写会变慢吗？单线程。</span></p>
  </blockquote>
  <p data-lake-id="u82a85503" id="u82a85503"><br></p>
  <p data-lake-id="u68e42807" id="u68e42807"><a href="https://www.yuque.com/hollis666/vhr2ge/abfis3" data-lake-id="uba02b014" id="uba02b014"><span data-lake-id="ua0e52826" id="ua0e52826">https://www.yuque.com/hollis666/vhr2ge/abfis3</span></a></p>
  <p data-lake-id="ucc3dd5ab" id="ucc3dd5ab"><span data-lake-id="u3e387d25" id="u3e387d25">​</span><br></p>
  <p data-lake-id="u4a231a91" id="u4a231a91"><a href="https://www.yuque.com/hollis666/vhr2ge/ry7g0lxzynxmneq7" data-lake-id="ud509d0d0" id="ud509d0d0"><span data-lake-id="uc7941d6f" id="uc7941d6f">https://www.yuque.com/hollis666/vhr2ge/ry7g0lxzynxmneq7</span></a></p>
  <p data-lake-id="ub0661f6e" id="ub0661f6e"><br></p>
  <p data-lake-id="uacc95106" id="uacc95106"><br></p>
  <blockquote data-lake-id="ua9f0e757" id="ua9f0e757" class="lake-alert lake-alert-color4">
   <p data-lake-id="u6ca869e2" id="u6ca869e2" style="text-align: left"><span data-lake-id="u5616d7ac" id="u5616d7ac" class="lake-fontsize-12">Key过期会立即删除吗？</span></p>
  </blockquote>
  <p data-lake-id="u35e7e22d" id="u35e7e22d"><br></p>
  <p data-lake-id="u2b9fee96" id="u2b9fee96"><a href="https://www.yuque.com/hollis666/vhr2ge/ds8qgg4zmt7l2kvp" data-lake-id="ua4c652b8" id="ua4c652b8"><span data-lake-id="u9d93011d" id="u9d93011d">https://www.yuque.com/hollis666/vhr2ge/ds8qgg4zmt7l2kvp</span></a></p>
  <p data-lake-id="u1acde934" id="u1acde934"><br></p>
  <blockquote data-lake-id="u952b6ca4" id="u952b6ca4" class="lake-alert lake-alert-color4">
   <p data-lake-id="ufaafad09" id="ufaafad09" style="text-align: left"><span data-lake-id="u2238974e" id="u2238974e" class="lake-fontsize-12">redis的big key问题？很大是多大？会有什么问题？如何解决呢？怎么拆？按照日期</span></p>
  </blockquote>
  <p data-lake-id="u73647ea3" id="u73647ea3"><br></p>
  <p data-lake-id="u59aea245" id="u59aea245"><a href="https://www.yuque.com/hollis666/vhr2ge/qiqc1r6r3catcev9" data-lake-id="u10471e8e" id="u10471e8e"><span data-lake-id="u60834793" id="u60834793">https://www.yuque.com/hollis666/vhr2ge/qiqc1r6r3catcev9</span></a></p>
  <p data-lake-id="ue9314414" id="ue9314414"><br></p>
  <p data-lake-id="u37f492b0" id="u37f492b0"><br></p>
  <blockquote data-lake-id="ufae53589" id="ufae53589" class="lake-alert lake-alert-color4">
   <p data-lake-id="u97f25557" id="u97f25557" style="text-align: left"><span data-lake-id="ueb4997aa" id="ueb4997aa" class="lake-fontsize-12">分库分表介绍下？单表数据量大导致查询慢，除了考虑分表之外，还有哪些方案？归档（冷热分离）、缓存、</span></p>
   <p data-lake-id="ufb6e1aa4" id="ufb6e1aa4" style="text-align: left"><span data-lake-id="u4ad0e269" id="u4ad0e269" class="lake-fontsize-12">数据量的话，你觉得做分库分表一定是一个好的方案吗？</span></p>
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  <p data-lake-id="u3a8fd6fb" id="u3a8fd6fb"><br></p>
  <p data-lake-id="u2a70bb22" id="u2a70bb22"><a href="https://www.yuque.com/hollis666/vhr2ge/dk6tpttlf2aex9ap" data-lake-id="u17e5ffcf" id="u17e5ffcf"><span data-lake-id="u9ff461fd" id="u9ff461fd">https://www.yuque.com/hollis666/vhr2ge/dk6tpttlf2aex9ap</span></a></p>
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